The ancestral graph and gene genealogy under frequency-dependent selection

Area of Science:

• Evolutionary genetics
• Population genetics
• Molecular evolution

Background:

• High polymorphism in self/nonself-recognition systems is often attributed to minority-advantage frequency-dependent selection.
• Understanding the genetic mechanisms maintaining diversity is crucial for evolutionary biology.

Purpose of the Study:

• To mathematically derive the ancestral graph for genes under minority-advantage frequency-dependent selection.
• To compare gene genealogies under haploid and diploid models.
• To investigate allele maintenance in spatial vs. non-spatial habitats for self-incompatibility systems.

Main Methods:

• Mathematical derivation of the ancestral graph for a haploid infinite-alleles model.
• Analysis of gene genealogy under weak selection.
• Modeling a one-locus haploid self-incompatibility system under strong selection.
• Comparison of spatial and non-spatial habitats.

Main Results:

• The gene genealogy under weak minority-advantage frequency-dependent selection is identical to that of a diploid model with heterozygote advantage.
• The study provides a rigorous mathematical framework for analyzing gene evolution under this selection model.
• Allele maintenance can differ significantly between spatial and non-spatial habitats in self-incompatibility systems.

Conclusions:

• Minority-advantage frequency-dependent selection provides a viable explanation for observed genetic polymorphism.
• The derived model offers insights into the evolution of self/nonself-recognition systems.
• Further research comparing different self-incompatibility models is warranted.